Examples:

Certain sets of words follow group rules of English grammar. Many rules of grammar are quite mathematical, with groups of words falling into building-blocks which all act the same way.

For example, the spelling rules are the same for ‘practice’, ‘licence’ and ‘advice’: the noun has a ‘c’, while the verb has an ‘s’.

One way of remembering this is that the word ‘noun’ comes before the word ‘verb’ in the dictionary; likewise ‘c’ comes before ‘s’, so the nouns are ‘practice/licence/advice’ and the verbs are ‘practise/license/advise’.

In fact, the confusion arises with ‘practice’ and ‘licence’ mainly because they sound the same with the ‘c’ or the ‘s’. However, with ‘advice’ and ‘advise’, there is a shift in sound, so there is no confusion at all. We can use this to our advantage: another way of knowing which to use is to replace the ‘practice’ or ‘licence’ word you want with ‘advice’ or ‘advise’ – this will tell you whether you need the ‘c’ or the ‘s’ spelling.